Small within-clutch variance in spiderling body size as a mechanism for avoiding sibling cannibalism in the wolf spider Pardosa pseudoannulata (Araneae: Lycosidae)

摘要: This study investigated why sibling cannibalism is so rare in the second instar of wolf spider Pardosa pseudoannulata (Araneae: Lycosidae), despite fact that cannibalistic and does not discriminate kin from non-kin. Laboratory experiments revealed relative size difference between cannibal its victim affected occurrence nymphal cannibalism, as other spiders. The degree difference, measured coefficient variation (CV), was smaller within a brood than among broods, but greater clutches might have been produced by less well fed females. Statistical analysis confirmed intraclutch would occur about 1% encounters siblings were randomly selected same clutch, because 99% intrabrood fell 10% which marginal value above frequent occurs. Thus, interclutch expected to much more frequently cannibalism. Considering potential benefit under food stress high mortality, even with sacrifice their full sibs, small variance spiderling body may be understood tactic adopted mother spiders avoid